Light emitting diodes (LED) have a relatively long lifespan, consume relatively small amounts of power, have a fast response speed, and are environmentally friendly. As a result, they are known as next-generation light sources, and have come to prominence as important light sources in various products such as lighting devices, backlights in display devices, and the like.
In particular, demand for white light emitting diodes is on the rise. In order to provide white light, phosphors may be used with LEDs. For example, in a light emitting device that emits UV light, red, green, and blue phosphors may be used. The phosphors are excited by the UV light to emit red light, green light, and blue light, respectively, to obtain white light. Alternatively, a blue light emitting device may be used to excite a yellow phosphor (a color complementary to blue) to emit yellow light, and to thereby obtain white light. In addition, without phosphors, white color may be obtained by combining separate light emitting devices that emit red, green, and blue visible light, respectively.
In this manner, a desired color of light may be obtained by combining light having various wavelengths generated by a light emitting device, and thus, a method for implementing various colors, other than white, is required.